Screw socket



Dec. 26, 1967 P. H. wlNTER 3,360,768

SCREW SOCKET Filed Nov. 2, 1966 '2 Sheeis-Sheet 1 IN VENTOI? PAUL H.WINTER A TTORNEYS P. H WINTER Dec. 26, 1967 SCREW SOCKET Filed Nov. 2,1966 2 Sheets Sheet 2 INVENTOR PAUL H. WINTER B ZQWMW 7,1 4 ATTR/VEYSUnited States Patent York Filed Nov. 2, 1966, Ser. No. 591,493 7 Claims.(Cl. 339-199) This invention relates to an Edison type lamp socket andmore particularly the screw threaded contact shell forming a part of thesocket.

The commonly used method for making screw threaded contact shells is totake a disc of suitable metal and draw it into a cup form, then punchthe necessary openings and finally roll the thread. These operationsrequire expensive equipment which will not produce shells at a veryrapid rate as compared to a conventional punch press operation.

In addition, a shell produced as indicated above has a substantialdisadvantage when used with the larger type bulbs since the shell isonly supported at the bottom by means of screws or rivets, the threadedportion being generally unsupported, particularly in porcelain socketswhere manufacturing variations inherent in the porcelain socket bodiesrequire clearance around the shell.

In the larger sockets, the amount of copper alloys used in the socketshell is substantial which adds appreciably to the cost of the unit.Increasing production and raw material costs have made it most desirableto provide means for reducing the cost of the socket shells.

In view of the foregoing, it is an object of this invention to providean Edison type lamp socket having a two-piece contact shell capable ofbeing completely produced on a punch press.

It is another object of this invention to provide a twopiece contactshell wherein only one piece is made of relatively expensive conductingmetal while the other is made of a less expensive relativelynon-conducting metal.

It is a further object to provide a socket having a twopiece contactshell so formed that assembly is both simple and rapid.

The above and other objects and advantages will become more apparentwhen considered in conjunction with the follOWing detailed descriptionand drawings, showing by way of example one preferred embodiment of theinvention.

In the drawings:

FIG. 1 is an exploded perspective view showing the twopiece contactshell and the socket housing into which they fit;

FIG. 2 is a top plan view of the socket with the twopiece contact shellpositioned therein, and

FIG. 3 is a cross sectional view taken along line 33 of FIG. 2 showingfurther details with regard to the mounting of the two-piece contactshell in the socket housing.

As illustrated in the various figures of the drawings, the socket ofthis invention comprises a porcelain housing 12 of generally cylindricalconfiguration having a cylindrical bore 14 with an open end 16 and base18. The base 18 has appropriate openings 20 and 22 to receive theterminal portions of the contacttshell. The bore wall 24 is providedwith a pair of opposed locator slots 26 and 28 and a pair of retaininggrooves 30 and 32. The slots and grooves are interpositioned andgenerally parallel to the longitudinal axis of the bore. These slots andgrooves extend up to the open end 16 of the housing. It should be notedthat these slots and grooves may be slightly tapered downwardly from theopen end of the housing to assist in assembly operations and facilitatepressing of the porcelain housing.

A two-piece contact shell 40 is interfitted within the housing 12. Thecontact shell comprises two separate curved shell elements 42 and 44which when assembled together form a shell unit substantiallycylindrical in shape 'ice and sized to fit within the housing bore 14.Cured shell elements 42 and 44 are of the same general height and aregrooved as indicated by numerals 46 to form in effect a continuousthread when the two elements are assembled together to receive alike-threaded lamp base.

It should be noted that the two-piece contact shell 40 which issubstantially cylindrical in shape may be slightly flattened on oppositesides, most advantageously between the two end portions of each curvedshell element, so that the diameter between these opposite flattenedportions is less than the general diameter of the contact shell. When alamp base is threaded into such a contact shell the resulting distortionof the two shell elements 42 and 44 will produce a generally cylindricalsocket providing a substantial amount of friction between the lamp bulbthreads and those of the socket shell to prevent loosening of the bulbdue to vibrations and the like.

The respective confronting edges 48 and 50 of curved shell elements 42and 44 have flanges 52 and 54 and flanges 56 and 58 respectivelyextending outwardly therefrom with respect to the cylinder formed by thetwo shell elements 42 and 44. It should be noted that flanges 56 and 58in curved element 44 are spaced from one another to form a gap 60. Apositioning and alignment lug 62 is formed between flanges 52 and 54 onshell element 42. It should be noted that this lug 62 extends outwardlyof and generally parallel to the edge 48 of the shell element 42 thuswhen the flanges 52 and 54 are brought into confronting engagement withflanges 56 and 58 the lug 62 will fit into gap 60 and thereby maintainalignment of the two shell elements 42 and 44. The gap 60 and the lug 62are properly sized to provide a close fit. Obviously, the positioninglug 62 could be located on both edges of the same shell element or onecould be located on each shell element at opposite edges. Thearrangement is a matter of choice as long as both edge portions of eachshell element have either the gap or the positioning lug.

Flange 56 on curved shell element 44 and flange 52 on curved shellelement 42 each have a bump 57 and 53 respectively on the uppermostportion of the flange facing away from the confronting flange. Thesebumps are generally struck from the flange by a well known dimplingprocess. Thus the bumps 53 and 57 face away from each other and providea tight fit when the assembled curved shell elements 42 and 44 areassembled and placed in the housing bore 14. Since the retainer grooves30 and 32 are tapered from top to bottom, these bumps are necessary toprovide a snug fit at the upper portion of the grooves where the grooveis widest.

Both curved shell elements 42 and 44 have locator members 66 and 68respectively struck therefrom intermediate their ends. These locatorsextend outwardly from the shell elements and are sized to fit intolocator grooves 26 and 28 in the housing.

Referring to FIG. 1, it will be observed that curved shell element 44has a terminal portion 70 extending downwardly therefrom. In addition,curved shell element 42 also has a projecting portion 72 similarlypositioned. In this particular embodiment curved shell element 44 ismade from a conventional current carrying metal such as a copper alloywhile curved shell element 42 may be made from a relatively poorconducting material which is less expensive such as steel.

In assembling the parts of the socket to form the completed article, thecurved shell elements 42 and 44 are brought together with their flanges52 and 54, confiront ing flanges 56 and 58 and positioning lug 62 fittedwithin gap 60. This arrangement of flanges and positioning lug is foundon both confronting end portions of the curved shell elements 42 and 44.The two curved shell elements so assembled form the substantiallycylindrical socket 40 which is then introduced into the open end 16 ofthe housing 14 with the locators 66 and 68 sliding down in locator slots28 and 26 respectively, and the flange p01: tions fitting down inretaining grooves 30 and 32. It should be noted that the socket shell 40is introduced into the housing bore 24 with the terminal portion 70 andprojecting portion 72 extending down through holes 20 and 22respectively. The projecting portion 72 and terminal 70 are twisted,bent or otherwise deflected to act as retainers for the socket shell 40.Terminal 70 may be formed in the conventional manner to receive aconductor or remain straight.

Although not a part of this invention, FIGS. 2 and 3 illustrate variousconventional features found in sockets. For example this socket isprovided with a spring type center contact 80 including a lower terminalportion 82. The contact 80 is positioned in an elongated opening 84having raised shoulders 36 and 88 on either side thereof. In additionthe socket shell 40 is vertically positioned within the housing bore bythe intermediate bearing portions 73 on projecting portion 70 andbearing portion 71 on terminal 70' both resting on the upper face 69 ofthe housing base 18.

It should .be noted that the assembled socket shell 40 is accurately andeasily oriented within the housing bore 14 by means of the locators 66and 68 fitting in locator grooves 26 and 28 and tapered slots 30 and 32which receive the confronting flange pairs of the curved shell elements42 and 44.

It will be readily apparent to those experienced in this field that thetwo-piece socket shell 40 wherein one piece is made from steel and theother from a better cur-rent conducting .metal represents :asubstantially economy by way of raw material. Secondly, such two-piecesockets can be completely made by well known punch press methods, hencerapid increase in production rate is .achieved. Even though theseeconomies are realized by this invention, there is no decrease instrength or serviceability as in the case of many cut-rate type sockets.

What is claimed is:

1. In an Edison type screw socket adapted to receive a threaded lampbase, a socket housing, said socket housing having a cylindrical borewith one end open, the bore wall having a pair of retaining groovesformed therein, said grooves being generally parallel to thelongitudinal axis of the bore and extending up to the open end, atwo-piece contact shell interfitted within the housing, said contactshell comprising two separate curved shell elements forming together agenerally complete cylinder sized to fit within the housing bore, saidtwo curved shell elements being grooved to form a thread when together,said thread being adapted to receive a likethreaded lamp base, therespective confronting edge portions of the shell elements having flangeportions directed generally outwardly with respect to the cylinderformed by the two shell elements, said two shell elements being fittedtogether with their flange portions in confronting relation to form thecylindrical socket shell which is fitted down into the bore of thehousing with the outwardly extending flange portions positioned in theretainer grooves so that the. socket shell is accurately assembled inthe housing.

2. The invention as set forth in claim 1 and wherein the bore wall isalso provided with a pair of locator grooves interpositioned withrespect to the retainer grooves and parallel therewith, said two shellelements having locator means extending outwardly therefrom, said 10-cator means fitting in the locator grooves when the two shell elementsare assembled and placed in the socket housing.

3. The invention as set forth in claim 1 and wherein at least one of theshell elements is made of a good electroconductive material and has aterminal extended therefrom.

4. In an Edison type screw socket adapted to receive a threaded lampbase, a socket housing, said socket housing having a cylindrical borewith one end open, the bore wall having a pair of opposed locator slotsand a pair of retaining grooves formed therein, the slots and groovesbeing interpositioned and generally parallel to the longitudinal axis ofthe bore, said slots and grooves extending up to the open end of thehousing, a two-piece contact shell interfitted within the housing, saidcontact shell comprising two separate curved shell elements formingtogether a generally complete cylinder sized to fit within the housingbore, said two curved shell elements having the same height and beinggrooved to form an interrupted thread adapted to receive a threaded lampbase, the respective confronting edge portions of the shell elementshaving flanges directed outwardly with respect to the cylinder formed bythe two shell elements, positioning means interengaging the respectiveconfronting flanges to maintain alingment between the two curved shellelements, each shell element having a locator extending outwardlytherefrom intermediate the ends thereof, said two curved shell elementsbeing fitted together with their respective flanges closely confrontingeach other and the positioning means maintaining alignment of the twoelements to form the cylindrical shell which is fitted into the bore ofthe housing with the confronting flanges retained within the retainergrooves and the locators in the locator grooves to accurately positionthe two-piece contact shell within the housing.

5. The invention as set forth in claim 4 and wherein one of the shellelements is made of a good electroconductive material and has a terminalportion extending therefrom.

6. The invention as set forth in claim 4 and wherein the two piececontact shell is formed slightly out of round whereby when the lamp baseis threaded thereinto the contact shell will slightly bind on the lampbase thread so as to prevent loosening of the lamp base due tovibration.

7. The invention as set forth in claim 4 and wherein each curved shellelement has a downwardly projecting strip-like portion adapted tocooperate with the housing to retain the contact shell within thehousing.

References Cited UNITED STATES PATENTS 955,438 4/1910 Russell 339-1991,519,774 12/1924 Eberhardt 339-73 1,817,879 8/1931 De Mask 339-733,165,370 1/1965 Laub 339-73 MARVIN A. CHAMPION, Primary Examiner.

R. STROBEL, Assistant Examiner.

1. IN AN EDISON TYPE SCREW SOCKET ADAPTED TO RECEIVE A THREADED LAMPBASE, A SOCKET HOUSING, SAID SOCKET HOUSING HAVING A CYLINDRICAL BOREWITH ONE END OPEN, THE BORE WALL HAVING A PAIR OF RETAINING GROOVESFORMED THEREIN, SAID GROOVES BEING GENERALLY PARALLEL TO THELONGITUDINAL AXIS OF THE BORE AND EXTENDING UP TO THE OPEN END, ATWO-PIECE CONTACT SHELL INTERFITTED WITHIN THE HOUSING, SAID CONTACTSHELL COMPRISING TWO SEPARATE CURVED SHELL ELEMENTS FORMING TOGETHER AGENERALLY COMPLETE CYLINDER SIZED TO FIT WITHIN THE HOUSING BORE, SAIDTWO CURVED SHELL ELEMENTS BEING GROOVED TO FORM A THREAD WHEN TOGETHER,SAID THREAD BEING ADAPTED TO RECEIVE A LIKETHREADED LAMP BASE, THERESPECTIVE CONFRONTING EDGE PORTIONS OF THE SHELL ELEMENTS HAVING FLANGEPORTIONS DIRECTED GENERALLY OUTWARDLY WITH RESPECT TO THE CYLINDERFORMED BY THE TWO SHELL ELEMENTS, SAID TWO SHELL ELEMENTS BEING FITTEDTOGETHER WITH THEIR FLANGE PORTIONS IN CONFRONTING RELATION TO FORM THECYLINDRICAL SOCKET SHELL WHICH IS FITTED DOWN INTO THE BORE OF THEHOUSING WITH THE OUTWARDLY EXTENDING FLANGE PORTIONS POSITIONS IN THERETAINER GROOVES SO THAT THE SOCKET SHELL IS ACCURATELY ASSEMBLED IN THEHOUSING.